John Rose

A Portland man pleaded guilty this week to murdering a 24-year-old woman in Boston 47 years ago.

John Michael Irmer, now 71, walked into Portland’s FBI field office in 2023 and confessed to killing and raping Susan Marcia Rose in 1979. He faces a mandatory sentence of life in prison without the possibility of parole, the Suffolk County District Attorney’s Office said in a statement.

At the court hearing in Boston on Wednesday, Rose’s sister said Rose, originally from Johnstown, Pennsylvania, was “caring, intelligent, adventuresome and curious.” She added that Irmer had not only taken Susan’s life, “he also ruined the lives of my parents and me.”

Construction workers found Rose’s bloodied, partially naked body in a building in Boston’s Back Bay neighborhood on Oct. 30, 1979.

Irmer told Portland FBI agents that he met Rose at a skating rink and took her to the under-construction building, where he “grabbed a nearby hammer and struck the woman on the head, killing her,” the Suffolk County DA’s office said. “He then raped her.”

Irmer said he left Boston the next day.

About two years after Rose died, another man was tried in her killing. He was found not guilty.

A DNA sample collected at the murder scene matched a sample investigators collected from Irmer after his 2023 confession.

Irmer told authorities that he had also murdered someone in a southern state. Detectives are investigating that claim.

Irmer said that, after a lifetime of crime — as well as serving a prison sentence in California — he “got sober, ‘found Jesus’ and needed to confess.”